Former Trump campaign manager Corey Lewandowski on Wednesday questioned the validity and enforceability of any nondisclosure agreements for White House employees. Lewandowski's comments come after the Trump campaign has accused ex-White House aide Omarosa Manigault Newman of violating a nondisclosure agreement.

Lewandowski, speaking at a breakfast hosted by the Christian Science Monitor in Washington, said he had to sign a nondisclosure when he joined a precursor of the Trump campaign in June 2015. But he questioned whether a public employee can be held to such an agreement, legally speaking, CBS News' Jack Turman reports.

"As it relates to a nondisclosure agreement for government employees, and I'm not an attorney just to be clear, I don't know if they are valid whatsoever," Lewandowski said. "Other than the disclosing of classified information, which is a crime in and of itself and has nothing to do with a nondisclosure agreement, I don't know how you hold a public employee, a government employee accountable to a nondisclosure agreement. I don't know if that is enforceable whatsoever. I have no idea."

"I think the issue is It has been a long term business practice of the Trump administration, the Trump Organization, to have non-disclosure agreements and it is something that they brought to the administration," Lewandowski continued. "I don't know who signed them. I don't know who didn't sign them. I have never seen one, because I didn't work for the government in any capacity there but I don't know if they are enforceable."

On Tuesday, White House press secretary Sarah Sanders said nondisclosure agreements in the White House are "very normal."

Lewandowski said he has never heard Mr. Trump use a racist slur, a point that has been questioned after Omarosa, in promoting her new book, claimed the president used a racial slur during a taping of "The Apprentice."

"I never heard the president use any type of racist words ever and I have never had a conversation with him about a potential tape that may or may not exist on any those issues ever," Lewandowski said.

Lewandowski, who said he's never worked with Omarosa, said he thinks she made the claims to promote her book.

"I think she has made the strategic decision that it was better for her to go out and say things which clearly seem to be unfounded or at least unverified on a number of occasions to promote her book," Lewandowski said.